The invention relates to an apparatus for collecting a continuous sample of a liquid for subsequent chemical analysis or other tests. While the sampling apparatus of the invention may be employed in any liquid analysis system, it is particularly suited for use with automated analysis equipment in municipal water supply and waste water monitoring systems, commercial process control systems, industrial fluid waste surveillance systems, and the like.
With increasing public concern over the quality of the environment, a significant need has arisen for equipment which is capable of accurately and economically testing various environmental conditions. Conventionally, if one wishes to measure the level of pollutant, the biological oxygen demand or some other parameter of a body of water, one would take a sample of the water and submit it to an appropriate quantitative chemical analysis. These chemical tests generally comprise a number of steps involving the mixing and reacting of a predetermined amount of the sample or reacted sample with specific quantities of various chemical agents.
These tests are best carried out individually by relatively highly skilled personnel. Naturally, if one wishes to use a test to obtain data continuously or at frequent intervals and thus construct an accurate and complete picture of the state of water quality over a period of time, conventional manual testing is quite expensive. If, on the other hand, the continuous analysis is to be performed with automated equipment, it is necessary to have a technique for taking a continuous sample from the body of water or other liquid to be tested.
For the proper operation of such systems employing automated test equipment, the sample must be representative of the liquid to be tested and chemically unaltered in order for the results of the subsequent analysis to give a true indication of its quality. Simply diverting a portion of the liquid from the body, however, will not provide acceptable results because the thus obtained sample tends to include solid particles which interfere with the proper operation of automatic analysis equipment. This problem is particularly accute in automated systems for monitoring of waste water or industrial effluents containing sand, debris such as hair, paper shreds, and other floating and suspended particles which tend to clog the equipment within a relatively short time. The sample collected for testing must, therefore, be not only representative, but in addition, must also be relatively free from foreign matter.
The object of this invention is to provide an economic and reliable apparatus for automatically obtaining from a liquid to be tested a continuous representative sample substantially free from solid particles which is capable of extended operation with minimal maintenance.